Will do. In the meanwhile, here are the differences between the
compile options from a kernel where ipfilter works (MARVELL_NAS)
versus PI (which is RPI with options IPFILTER_LOG, IPFILTER_LOOKUP,
IPFILTER_COMPAT and pseudo-device ipfilter):

This builds for me.

Do you have any extra patches in your tree? On a NetBSD 6 system:
cvs checkout -P src
cd src